The Russian magazine Vlast (in Russian) is reporting that a serious fire occurred aboard a Russian submarine in 29 December 2012 2011.

The fire was covered on television  news (YouTube is a goldmine) and someone placed a great many photos online at a military-oriented internet forum,  As in the case of the Plushkino traffic jam, I am amazed by the detail available in open sources about accidents involving Russian strategic forces.

As far as I can tell, what makes the report in Vlast so interesting is its careful detail, resulting in the revelation that it may have been armed in dry-dock:

В реальности Россия почти сутки находилась на пороге крупнейшей техногенной аварии со времен Чернобыля: в 6 км от Мурманска ярким пламенем горел атомный подводный стратегический ракетоносец К-84 “Екатеринбург”, на борту которого находились ракеты с ядерными боеголовками, торпеды и два атомных реактора.

That is, as far as I can tell, Russian for something like “largest man-made disaster since Chernobyl” as flames burned from a ballistic missile submarine  ”carrying nuclear missiles, torpedoes and two nuclear reactors.”  I don’t think the authors are thinking the INES scale, by the way, just that failure to control the fire could have resulted in explosions that would have ripped open the reactor vessel, making a very nasty mess.

I should note that, should such an event occur on a US nuclear submarine, the outcome could also be very bad.  There was a substantial debate in the United States during the 1980s about the dangers from plutonium dispersal if a W76, which does not utilize insensitive high explosives, were to detonate if dropped or set on fire.  This debate culminated in the 1990 Report of the Panel on Nuclear Weapons Safety of the Committee on Armed Services House of Representatives, better known as the Drell Report.  (John Harvey and Stefan Michalowsk revived the argument in a monograph and  journal article.)